Local advertising startup Yext has a new chairman, Michael Walrath . Walrath was the founder and CEO of Right Media, an online advertising exchange which he sold to Yahoo for $850 million in 2007. Since then he's been investing and starting other projects. One of his biggest investments is Yext, where he is the largest individual shareholder outside the company. Walrath became a board member of Yext about a year and a half ago when he first invested in the company's $25 million series B . Now that he is taking chairman role, he will be at Yext's New York City offices once a week plotting the overthrow of the online local advertising world with CEO Howard Lerman. (The two are pictured here enjoying some green St. Patrick's Day champagne yesterday when they told me the news).